Tasmanian giant crab

Tasmanian giant crab
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
Infraorder: Brachyura
Family: Menippidae
Genus: Pseudocarcinus
H. Milne-Edwards, 1834
Species:
P. gigas
Binomial name
Pseudocarcinus gigas
(Lamarck, 1818)
Synonyms [1]

Cancer gigas Lamarck, 1818

The Tasmanian giant crab (Pseudocarcinus gigas), also known as the giant deepwater crab, giant southern crab, queen crab, or bullcrab, is a very large species of crab that resides on rocky and muddy bottoms in the oceans off Southern Australia.[2][3] It is the only extant species in the genus Pseudocarcinus.[4]

Habitat[edit]

The Tasmanian giant crab lives on rocky and muddy bottoms in the oceans off Southern Australia on the edge of the continental shelf at depths of 20–820 metres (66–2,690 ft).[2][3] It is most abundant at 110–180 metres (360–590 ft) in the summer and 190–400 metres (620–1,310 ft) in the winter.[3] The seasonal movements generally follow temperature as it prefers 12–14 °C (54–57 °F).[3] The full temperature range where the species can be seen appears to be 10–18 °C (50–64 °F).[5]

Description[edit]

Lithograph of a male Pseudocarcinus gigas.
Tasmanian giant crab in Sydney Aquarium, Australia

The Tasmanian giant crab is one of the largest crabs in the world, reaching a mass of 17.6 kg (39 lb) and a carapace width of up to 46 cm (18 in).[6] Among crabs, only the Japanese spider crab (Macrocheira kaempferi) can weigh more.[5] Male Tasmanian giant crabs reach more than twice the size of females,[7] which do not exceed 7 kg (15 lb).[6] Males have one normal-sized and one oversized claw (which can be longer than the carapace width[5]), while both claws are normal-sized in females.[6] This crab is mainly whitish-yellow below and red above; the tips of the claws are black.[8] Small individuals are yellowish-and-red spotted above.[5]

Behaviour[edit]

The Tasmanian giant crab feeds on carrion and slow-moving species, including gastropods, crustaceans (anomura and brachyura) and starfish.[3][7] Cannibalism also occurs.[3] They breed in June and July, and the female carries the 0.5–2 million eggs for about four months.[7] After hatching, the planktonic larvae float with the current for about two months before settling on the bottom.[5] The species is long-lived and slow-growing; juveniles moult their carapace every three-four years and adult females about once every nine years.[5][6] This greatly limits the breeding frequency, as mating is only possible in the period immediately after the old carapace has been shed, and the new is still soft.[6]

Fishery[edit]

The Tasmanian giant crab has been commercially fished in Tasmanian waters since 1992 and a minimum size was established in Australia in 1993.[7] Fishing is typically by pots in water deeper than 140 m (460 ft).[6] Following concerns surrounding the sustainability of catch numbers, the total allowable catch was adjusted in 2004 to 62.1 tonnes (137,000 lb).[9] Twenty-five operators competed for the catch in 2005, delivering a total catch valued at about A$2 million.[9] The Tasmanian giant crab is very long-lived and slow-growing, making it vulnerable to overfishing.[7] Before export, they are sometimes kept alive in tanks with water that is 10–14 °C (50–57 °F).[3]

References[edit]

  1. ^ Peter Davie (2010). "Pseudocarcinus gigas (Lamarck, 1818)". World Register of Marine Species. Retrieved October 9, 2010.
  2. ^ a b Palomares ML, Pauly D, eds. (2013). "Pseudocarcinus gigas" in SeaLifeBase. December 2013 version.
  3. ^ a b c d e f g Levings, A.H. & P.C. Gill (2010). Seasonal Winds Drive Water Temperature Cycle and Migration Patterns of Southern Australian Giant Crab Pseudocarcinus gigas. In: G.H. Kruse, G.L. Eckert, R.J. Foy, R.N. Lipcius, B. Sainte-Marie, D.L. Stram, & D. Woodby (eds.), Biology and Management of Exploited Crab Populations under Climate Change. ISBN 978-1-56612-154-5. doi:10.4027/bmecpcc.2010.09
  4. ^ P. K. L. Ng, D. Guinot & P. J. F. Davie (2008). "Systema Brachyurorum: Part I. An annotated checklist of extant Brachyuran crabs of the world" (PDF). Raffles Bulletin of Zoology. 17: 1–286.
  5. ^ a b c d e f Poore, G.C.B. (2004). Marine Decapod Crustacea of Southern Australia: A Guide to Identification. CSIRO Publishing. p. 445. ISBN 0-643-06906-2.
  6. ^ a b c d e f Tasmanian Museum and Art Gallery (12 February 2013). "Giant crab". ABC Hobart. Retrieved 3 September 2017.
  7. ^ a b c d e D. R. Currie & T. M. Ward (2009). South Australian Giant Crab (Pseudocarcinus gigas) Fishery (PDF). South Australian Research and Development Institute. Fishery Assessment Report for PIRSA. Retrieved 9 December 2013.
  8. ^ N. Coleman (1991). Encyclopedia of Marine Animals. Blandford, Villiers House. p. 107. ISBN 0-7137-2289-4.
  9. ^ a b "Giant crab fishery". Department of Primary Industries, Parks, Water and Environment. December 15, 2009. Retrieved January 1, 2010.

External links[edit]

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